I have been a sponsor for 20 years. From what I can tell, the children must have a letter writing day once a quarter. I get a letter from them once a quarter. In my experience, the letter will appear on the website or app long before it is mailed.

Hi Pesh! Is this the first letter from your child that you are waiting on? It can take up to four months to receive the first letter from your child. If this isn't the first letter, the child has 60 days once she receives your letter to write a reply letter and get it back to the country office for processing. I know how hard it is to wait for a letter from your child! I always anticipate mine too :). If you can hang in there a little longer, you will receive a letter from your child in the coming months!